I'm a fan of live music and a patron of online communities such as eTree.org, where music junkies swap copyright-free music. So I was stung when I recently tried to download a live recording of a Dave Matthews concert only to discover that my BitTorrent client was dead in the water.

My system and Net connection checked out fine, so paranoia immediately set in: Was my Internet service provider, RCN, blocking BitTorrent? I called RCN and the tech I spoke to confirmed my suspicions, telling me that the ISP had added BitTorrent to its list of prohibited programs because many people use the software to download copyrighted material. The fact that the concert I was trying to download was copyright-free didn't sway him.

Later I called RCN's press department as a reporter, and the story changed. The ISP's spokesperson told me that the customer support rep I had talked to earlier misspoke. RCN has never intentionally blocked peer-to-peer traffic, the spokesperson said, and it supports the principles behind Net neutrality. Within 24 hours, my bandwidth-related problems with BitTorrent vanished.

Of course, most people can't call their ISP and (honestly) identify themselves as professional journalists. But that doesn't mean you have no recourse if your ISP starts blocking your file-sharing activities. A number of tips and tools can help you determine whether you're facing a BitTorrent blockade and, if so, help you get around it.

Vuze, a company that makes peer-to-peer software and uses the platform to distribute content, published a study in April in which it concluded that all U.S. broadband providers--including AT&T, Cablevision Systems, Charter Communications, Comcast, Cox Communications, Qwest, Time Warner Cable, and Verizon--disrupt peer-to-peer traffic. Vuze asserted that these ISPs regularly send "false reset" messages to the Vuze software with the aim of slowing file transfers.&#160;&#160;

AT&T has flatly denied this claim. Subsequently, Vuze has softened its charge against ISPs, stating that "Our data collection was credible and transparent, but not conclusive," in the words of Jay Monahan, Vuze general counsel.

Other ISPs have acknowledged imposing some limitations on peer-to-peer traffic. Comcast first denied but now admits to interrupting access to file-sharing programs such as BitTorrent. Comcast executive vVice president David L. Cohen explained at a Federal Communications Commission hearing last February that disrupting BitTorrent traffic was a reasonable method of traffic management during busy usage periods.

Time Warner Cable spokesperson Alex Dudley says that his company takes reasonable steps to manage its network, including limiting bandwidth to applications such as peer-to-peer software.